We propose to study and compare the clonal properties of biopsies of human bladder cancer implanted into semi-solid culture and into immune-deprived mice, and to seek clinical correlation of these properties with the course of the disease. Tissue will be obtained from patients with mucosal disease, from patients with invasive disease referred for radical radiotherapy, and from patients with advanced disease undergoing chemotherapy. Clonogenicity of cell suspensions obtained from bladder irrigation or from dissociation of biopsies will be assessed in semi-solid media. We shall study genetic variability, morphological features, physical properties such as cell size and density, proliferative rate and self-renewal capacity. Tissue obtained from the same patients will be implanted into mice that have been rendered immune-suppressed by thymectomy followed by treatment with Cytosine Arabinoside and Radiation. Percentage takes, growth rate, histology and metastasis formation will be monitored and compared with clinical parameters. Comparison of generation of tumors in mice and colonies in culture from cell suspensions fractionated by cell size or density, plus comparison of clonal properties in culture of primary biopsies and xenografts generated from them, will provide evidence for identity or non-identity of clonogenic cells selected in vivo and in culture. We shall study the response of clonogenic cells from human bladder cancer to radiation and drugs following treatment in culture and of second generation xenografts in mice. We shall seek to correlate these responses, and to compare them with the clinical response of our patients who are followed carefully according to clinical protocols.